First off, I'm still a newbie 'round here and not sure if this should be a blog post instead. This is my first time starting a 'discussion'. I figure it's easier to reply here if someone has a question or new idea. So anyway...

I'm a tinkerer. I can't help it. I built one of the PVC racks that was posted here where the guitars sit on top of a dual rail with the necks hanging down. It worked great, but after a few months I wanted to try something different. Yesterday I was looking at it and thought, hey I could convert that to a leaning rack like 1 of those travel guitar cases. So today I went at it. I'm sooooo happy with it! Thought I'd share in case it helps someone else. If you build one, you don't have to follow my dimensions exactly. Do what's right for your needs, tweak it, make it better... But to get you started, here's the design I used.

Notice the front lower rail is higher than the back lower rail (only by 1 inch), but this makes the guitars lean back against the top rail. This is key! The gap between the 2 bottom rails allows your neck through tail to hang down.

At first I did a quick assembly without the elevated sides (they look like arms on a chair). It worked great, but I decided to put the sides on to prevent a cbg domino slide onto the floor if my crazy dogs rammed into it while wrestling. 

The whole thing's made from 1/2" PVC. I inserted a 1/2" aluminum tube inside the front lower rail which bears all the weight to keep it from bowing. Works really well & keeps it light. I tried a dowel, but it didn't stop the bowing.

I ended up with a lot of extra PVC vs where I started from with my original hang down rack. Like I said, I liked that design, but I'm a tinkerer and wanted to mix it up. I have a feeling a lot of people around here are tinkerers too! :)

Hope this helps!